From 0827e040e0071bdc59b26d6a8936459e1304f682 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Fri, 12 Feb 2010 01:30:21 +0000 Subject: Add a new pass on machine instructions to optimize away PHI cycles that reduce down to a single value. InstCombine already does this transformation but DAG legalization may introduce new opportunities. This has turned out to be important for ARM where 64-bit values are split up during type legalization: InstCombine is not able to remove the PHI cycles on the 64-bit values but the separate 32-bit values can be optimized. I measured the compile time impact of this (running llc on 176.gcc) and it was not significant. llvm-svn: 95951 --- llvm/lib/CodeGen/LLVMTargetMachine.cpp | 1 + 1 file changed, 1 insertion(+) (limited to 'llvm/lib/CodeGen/LLVMTargetMachine.cpp') diff --git a/llvm/lib/CodeGen/LLVMTargetMachine.cpp b/llvm/lib/CodeGen/LLVMTargetMachine.cpp index 40e015067f4..3c12afaacf6 100644 --- a/llvm/lib/CodeGen/LLVMTargetMachine.cpp +++ b/llvm/lib/CodeGen/LLVMTargetMachine.cpp @@ -299,6 +299,7 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM, if (OptLevel != CodeGenOpt::None) { PM.add(createOptimizeExtsPass()); + PM.add(createOptimizePHIsPass()); if (!DisableMachineLICM) PM.add(createMachineLICMPass()); if (!DisableMachineSink) -- cgit v1.2.3